In a large skillet, over medium heat, cook beef until browned and crumbly; drain. Stir in broth and Worcestershire sauce, and cook 4 - 5 minutes until most liquid is absorbed. Season with salt and pepper, and remove beef; set aside.
In same skillet, over medium heat, add oil. Add vegetables and cook 5 - 6 minutes until softened. Transfer beef to skillet, mix well, add cheese, and then cover skillet until cheese melts.
Divide between 6 bowls to serve.